1. Field of the Invention
The application relates to polyetheramide molding compositions with excellent heat resistance and hydrolysis resistance, suitable for the extrusion of flexible pipes, and also for the production of flexible blow-molded articles.
2. Discussion of the Background
Plasticized semicrystalline polyamide molding compositions, in particular based on nylon-11 or nylon-12, have long been extruded to give pipes for use in automotive construction, because they have excellent mechanical strength and chemical resistance. However, these moldings stiffen after a short period of use at the high usage temperatures increasingly demanded in recent times under the engine hood, due to the volatility of the external plasticizers used. In addition, when exposed to pressure they have a tendency toward irreversible deformation at the increased usage temperatures now demanded which are in the range of from 110 to 150° C. Although these disadvantages can be avoided by using molding compositions based on higher-melting polyetheresteramides, for example as described in EP-A-0 095 893, this class of polyamide elastomer is unsuitable for producing pipes usable for the abovementioned applications, because with respect to the hydrolysis resistance also demanded for this application these molding compositions fall far short of the resistance of traditional polyamide molding compositions, and fail after just a few weeks.